The Plant Man column
for publication week of 12/25/05 - 12/31/05
The Plant Man
by Steve Jones
Oak trees targeted by voracious caterpillars
A new year is upon us and already landscape and garden enthusiasts are
anticipating the coming spring! Here are some recent questions I
received from readers of this column. I'm always happy to receive
your comments and questions at firstname.lastname@example.org
QUESTION: "My 10 year old oak tree has lost almost all of the leaves.
I discovered a lot of caterpillars. I have hardly any leaves left. I
have gotten rid of the caterpillars, but my tree looks very barren.
Will it come back or is there something special I should do ?" -
ANSWER: Caterpillars can be frustrating! In some cases, caterpillars
can totally defoliate a tree. According to an online article published
by the Extension Service of Texas A&M, when a tree is defoliated it can
become stressed and serious damage can occur. Green leaves manufacture
energy that allows the tree to grow and maintain its natural vigor.
Once a tree is defoliated, it essentially stops manufacturing sugar
which slows tree growth.
Moreover, stressed trees are susceptible to attack from various
diseases and wood-boring insects. What to do? Well, caterpillar
populations are generally cyclic and they rarely appear year after
year, so you could simply do nothing and see if the tree comes back
next spring. If you see evidence of leaf-roller infestation at that
time, you could spray the leaves with a carbaryl product such as Sevin
or any similar product designated for the control of caterpillars or
To find out more about caterpillars and how to control them, I suggest
you read the entire article at
http://insects.tamu.edu/extension/publications/E206.pdf and you can
easily click on a direct link from this column archived at my Web site
www.landsteward.org under the Plant Man heading.
QUESTION: "I purchased 2 Grace Smoke Trees and planted them in early
spring this year. Both plants are close to 5 ft. tall. They are healthy
and leafed out well in the spring. I am wondering if I should prune
them back a bit in the spring to help them bush out more, and...if so,
how much should I prune? One plant has a v-shape trunk (with 2 main
stalks) at the base and the other plant is one long trunk. Neither tree
has any limbs yet. One more question: should I fertilize and when is
the best time for these trees? Hope you can help and thanks so much
for your advice." - Trish Joyner
ANSWER: Pruning these plants now (or at any time during fall/winter)
will promote a more intense foliage color. Also, they do flower better
on new growth. Treat them the same way you would crape myrtles. Cut
them back anywhere from one third to one half of the plant. It will
force more branching and all of this new growth will produce more
flowers and striking foliage.
The rule of thumb on fertilizing deciduous trees and shrubs is to wait
for them to leaf out in spring before applying your first round of
fertilizer and be sure to follow the directions on the package to not
overdo it. I prefer the granular fertilizer, but that's just a
personal choice. Adding compost or other natural products to the soil
around the immediate base of plants can give them as much of a boost as
fertilizer can. Natural products will not harm the plants and will only
help to build your soil.
QUESTION: "Can I put my lawn clippings such as leaves and grass
directly into my garden to till in in the spring or would this be more
of a problem later?" - Neal Goble
ANSWER: It is far better to compost them first. Among the many reasons,
composting the clipping first will eliminate most of the weed seed
before you put it in your garden. Go to my Web site and find two recent
Plant Man columns that include a lot of information on composting.
QUESTION: "I have an arborvitae in a large container, will it survive
in a container over winter?" - Adrianne
ANSWER: No, You should either bury the container in the soil so that
it can be insulated or take out of the container and plant.
The Plant Man is here to help. Send questions about trees, shrubs and
landscaping to email@example.com For resources and additional
information, or to subscribe to Steve's free e-mailed newsletter, go